Derivatives of glycols,glycol ethers and glycol esters

ABSTRACT

NOVEL GLYCOL URETHANES HAVE THE GENERAL FORMULA:   R1-NH-COO-(R2-O)N-R3   WHEREIN R1 IS AN ALKYL GROUP CONTAINING FROM 1 TO 4 CARBON ATOMS, AN ALLYL GROUP OR THE GROUP   -R6-NH-COO-(R2-O)N-R7;   R2 IS AN ALKYLENE RADICAL CONTAINING FROM 1 TO 4 CARBON ATOMS; R3 IS HYDROGEN, AN ALKYL RADICAL CONTAINING FROM 1 TO 4 CARBON ATOMS, OR ONE OF THE GROUPS   R4-CO- OR R1-NH-CO-; R4   IS AN ALKYL RADICAL CONTAINING FROM 1 TO 4 CARBON ATOMS; R6 IS AN ALKYLENE GROUP CONTAINING FROM 1 TO 10 CARBON ATOMS; R7 IS AN ALKYL GROUP CONTAINING FROM 1 TO 4 CARBON ATOMS OR THE GROUP   R4-CO-;   AND EACH N IS THE SAME OR DIFFERENT AND IS AN INTEGER OF FROM 1 TO 6 AND WHEN N IS AN INTEGER GREATER THAN 1, EACH R2 MAY BE THE SAME OR DIFFERENT. A METHOD OR PREPARING THE NOVEL COMPOUNDS AND HYDRAULIC FLUIDS CONSISTING OF, OR COMPRISING THE NOVEL COMPOUNDS ARE ALSO DESCRIBED.

United States Patent U.S. Cl. 252-77 9 Claims ABSTRACT OF THE DISCLOSURE Novel glycol urethanes have the general formula:

wherein R is an alkyl group containing from 1 to 4 carbon atoms, an allyl group or the group -R|NHC-O/R2O) B1;

R is an alkylene radical containing from 1 to 4 carbon atoms; R is hydrogen, an alkyl radical containing from 1 to 4 carbon atoms, or one of the groups R40- 01 RqNH-fii-fi R4 is an alkyl radical containing from 1 to 4 carbon atoms; R, is an alkylene group containing from 1 to carbon atoms; R-, is an alkyl group containing from 1 to 4 carbon atoms or the group R4C; ll 0 and each n is the same or difi'erent and is an integer of from 1 to 6 and when any n is an integer greater than 1, each R may be the same or diflerent.

A method of preparing the novel compounds and hydraulic fluids consisting of, or comprising the novel compounds are also described.

This is a division of application Ser. No. 122,558, filed Mar. 9, 1971 and now abandoned.

The invention relates to derivatives of glycols, glycol ethers and glycol esters, the preparation of the derivatives and hydraulic fluids containing them.

According to the present invention there are provided glycol urethanes having the general formula:

wherein R is an alkyl group containing from 1 to 4 carbon atoms, an allyl group or the group is an alkyl radical containing from 1 to 4 carbon atoms; R, is an alkylene group containing from 1 to 10 R is hydrogen, an alkyl radical containing from 1 to 4 carbon atoms, or one of the groups R is an alkyl radical containing from 1 to 4 carbon atoms; R is an alkylene group containing from 1 to 10,

preferably from 2 to 8, carbon atoms; R, is an alkyl group containing from 1 to 4 carbon atoms or the group ra l and each n is the same or different and is an integer of from 1 to 6, preferably 1 to 4, more preferably 2 or 3, and when any n is an integer greater than 1, each R may be the same or different.

The compounds of the present invention may be readily prepared by reacting an alkyl isocyanate or diisocyanate with the appropriate glycol mono-ether, polyoxylakylene glycol mono-ether, glycol mono-ester, polyoxyalkylene glycol mono-ester, glycol or polyoxyalkylene glycol, and such preparation is within the scope of the present invention.

Accordingly the invention further provides a process for the preparation of glycol urethanes which process comprises reacting an alkyl isocyanate or diisocyanate with a glycol mono-ether, polyoxyalkylene glycol mono-ether, glycol mono-ester, polyoxyalkylene glycol mono-ester, glycol or polyoxyalkylene glycol to produce a compound having the general formula:

wherein R R R and n are as hereinbefore defined.

The reaction may be carried out at a temperature of from room temperature to C, optionally in the presence of an inert solvent such as dimethyl formamide, petroleum ether, benzene or toluene. If desired the reaction may be carried out in an inert atmosphere e.g. nitrogen.

The compounds are believed to be new, and are useful as functional fluids or components for functional fluids sucn as hydraulic fluids.

The compounds, or mixtures thereof, particularly suitable for use as hydraulic fluids are those having a boiling point of at least C., preferably at least 230 C., more preferably at least 260 C., and a kinematic viscosity at 40 C. of not more than 5000 cst., preferably not more than 2000 est.

In particular, certain of the compounds are useful as additives or components in hydraulic brake and clutch fluids when low hygroscopicity is of prime consideration. In recently developed hydraulic brake and clutch fluids having low hygroscopicity, it has been the practice to include small amounts of glycols and glycol ethers in order to render these fluids miscible with up to 5% of water. These glycols or glycol ethers impart a small degree of hygroscopicity to the fluids. The compounds of the present invention have very low hygroscopicities and are also partially miscible with water. Furthermore, the compounds of the present invention are particularly good in respect of their rubber swell characteristics, many of them when used alone shrinking the rubbers used in hydraulic brake and clutch systems. Thus the compounds of the present invention may be suitably blended with other compounds which are suitable for use as hydraulic fluids but which swell the rubbers used in the hydraulic brake and clutch systems.

The invention therefore includes a hydraulic fluid consisting of, or comprising, a compound in accordance with the present invention or a mixture of such compounds.

In one aspect of the present invention the hydraulic fluid comprises from 1% to 99%, by weight based on the weight of the hydraulic fluid, of the compound or mixture of compounds.

Preferably the hydraulic fluid comprises from 5% to 99%, more preferably 5% to 80%, especially 10% to 70%, of the compound or mixture of compounds. When 3 used as rubber shrinking additives the compounds of the present invention are preferably used in amounts from 1% to 10%, more particularly 2% to 5%.

It is particularly preferred that the hydraulic fluid should have a viscosity of not more than 5000 cst., preferably not more than 2000 cst., at 40 C. and a boiling point of at least 230 C., particularly more than 260 C.

Particularly useful fluids which may be blended with or contain the compounds of the present invention include (poly)oxyalkylene glycol ether esters of dicarboxylic acids, such as those described in British Patent Specification No. 1,083,324, or esters of acetic, propionic or butyric acids with dior polyoxyalkylene glycols or combinations of these two types of esters as disclosed in Belgian Patent Specification No. 749,904. Other base fluids with which the compounds of the present invention may be blended are the well-known polyoxyalkylene glycol and glycol ether fluids, which are exemplified in UK. Patent Specification No. 1,055,641. Further components which may be present are the orthoesters and the borate esters disclosed in co-pending United States Application Ser. No. 251,524, filed May 8, 1972 and Ser. No. 219,504, filed Jan. 20, 1972 respectively.

It is to be understood that the hydraulic fluids of the present invention may also include conventional hydraulic fluid additives such as lubricity additives, antioxidants, corrosion inhibitors, etc.

Typical additives which may be used in the hydraulic fluids of the invention are lubricity additives selected from castor oil or castor oil treated in various ways, for example,

Firsts Castor Oil,

Castor oil to Specification DTD72 Blown castor oil, i.e. castor oil blown with air or oxygen while being heated.

Special Pale Blown Castor Oil, i.e. a similarly blown castor oil.

"Hydricin 4 i.e. a commercially available ethylene/oxide/ propylene oxide treated castor oil.

Other lubricity additives which may be incorporated in hydraulic fluids in accordance with the present invention include borate esters e.g. tricresyl borate and phosphoruscontaining esters, especially phosphates e.g. tricrcsyl phosphate.

The hydraulic fluids of the present invention may also include minor proportions of polyoxyalkylene glycols or ethers thereof e.g. those sold by Union Carbide Corporation under the Registered Trade mark Ucon, particularly those of the LB and HB series. Suitable examples of these polyoxyalkylene glycols and their ethers and esters are given in British Patent Specification No. 1,055,641. Other suitable lubricity agents are orthophosphate or sulphate salts of primary or secondary aliphatic amines having a total of from 4 to 24 carbon atoms, dialkyl. citrates having an average of from 3% to 13 carbon atoms in the alkyl groups, aliphatic dicarboxylic acids and esters thereof, specific examples being Diamylamine orthophosphate Dinonylamine orthophosphate Diamylamine sulphate Dinonyl citrate Di(2-ethyl hexyl)citrate Polyoxyethylene sebacate derived from a polyoxyethylene glycol of M.W. 200

'Polyoxyetbylene azelate derived from a polyoxyethylene glycol of M.W. 200

Polyoxyethylene adipate derived from a polyoxyethylene glycol of M.W. 200

Polyoxye'thylenelpolyoxypropylene glutarate derived from mixed polyoxyglycols of average M.W. of about 200 Glutaric acid Azelaic acid Sebacic acid Succinic acid Di ethyl sebacate Di 2-ethyl hexyl sebacate Di iso octyl azelate Unsaturated aliphatic acids or their salts may also be used e.g. oleic acid or potassium ricinoleate.

Corrosion inhibitors which may be used in the present invention may be selected from heterocyclic nitrogen containing compounds, e.g. benzotriazole and benzotriazole derivatives such as those described in British Patent Specification No. 1,061,904 or mercapto benzothiazole. Many amines or derivatives thereof are also suitable as corrosion inhibitors, for example di n-butylamine di n-amylamine cyclohexylamine and soluble salts thereof e.g. cyclohexylamine carbonate.

Phosphites are also good corrosion inhibitors e.g.

Tri phenyl phosphite Di isopropyl phosphite and certain inorganic salts may be incorporated e.g. sodium nitrate.

Other additives which may be included are antioxidants such as diarylamines e.g. diphenylamine, p,p'-dioctyl-diphenyl-amine, phenyl a: naphthylamine or phenyl B- naphthylamine. Other suitable antioxidants are those com monly known as hindered phenols which are exemplified y 2,4 dimethyl-G-t-butyl phenol 2,6 di-t-butyl-4-methylphenol 2,6 di t-butyl phenol 1,1 bis (3,5 di-t-butyl-4-hydroxyphenyl)methane 3,3,5,5' tetra-t-butyl-4-4'-dihydroxydiphenyl 3-methyl 4,6-di-t-butyl phenol 4-methyl-2-t-butyl phenol Yet further additives which may be used are phenothiazine and its derivatives, for example those having alkyl, or aryl, groups attached to the nitrogen atom or to the aryl groups of the molecule.

Other additives which may be used include alkylene oxide/ammonia condensation products as corrosion inhibitor, for example the propylene oxide/ ammonia condensation product described in Belgian Pat. No. 749904. Further lubricity additives which may be used are complex esters, such as that sold under the trade name Reoplex 641 and also described in Belgian Pat. No. 749904. Moreover, long chain (e.g. C primary amine corrosion inhibitors and polymerized quinoline resin antioxidants, as described in Belgian Pat. No. 749904, may be used, examples of such amines and resins being the commercially morpholine triethanolamine available materials Armeen 12D and Agerite resin D respectively.

Conventional additives such as those hereinbefore described are normally employed in small amounts such as 0.05% to 10% for example, 0.1% to 2% by weight.

In another aspect of the present invention there is provided a hydraulic system containing the hydraulic fluids of the present invention. In a further aspect there is provided a method of transmitting power, which method comprises introducing the hydraulic fluids of the present invention into a hydraulic system and transmitting power by applying pressure thereto.

The compounds of the present invention, their preparation and hydraulic fluids containing them, will now be illustrated with reference to the following examples.

EXAMPLE 1 Methyl diglycol N-ethyl urethane 94 g. (0.78 mole) of diethylene glycol monomethyl ether which has been dried over molecular sieves for 24 hours and 50 g. (0.705 mole) of ethyl isocyanate were slowly mixed, each dissolved in 40 ml. of dimethyl form- 7 out in the following Table III, in which Base Blend A consisted of the following components:

Percent Di(monomethyl ether of dicthyl glycol)nylonate 39 Triethylene glycol dipropionate (TEGDP) 45 Monomethyl ether of triethylene glycol Monoethyl ether of triethylene glycol 5 Reoplex 641 (a commercially available lubricity additive) 3 AmineA 3 Plus the following combination of additives:

Percent Di-n-butyalmine (DBA) 0.05 Benzotriazole (BTZ) 0.05 Triphenyl phosphite (TPP) 0.15

Commercially available primary, saturated, straight chain aliphatic monoamine (95% primary, 5% secondary and tertiary amines; the alkyl chains being C12; C14 and C) Agerite Resin D (commercially available polymerized trimethyl dihydro quinoline resin) 0.05

Amine A was a condensation product of propylene oxide (5.5 moles) with ammonia (1 mole) and Reoplex 641 was a complex ester of molecular weight about 712 derived from neopentyl glycol and a mixture of sebacic, azelaic and adipic acids in respective proportions, determined by analysis, of 53%, 5% and 38%. The nylonate ester was an ester of a mixture of dicarboxylic acids as described in UK. Patent Specification No. 1,083,324.

Further blends tested were as follows:

This was found to be a useful hydraulic fluid having a boiling point of 285 C. and a viscosity of 1775 cst. at 40 C. Rubber swell tests (at 120 C.) on the synthetic 8 rubber hereinbefore described resulted in rubber swell of 9.3% after 3 days, 9.1% after 1 week and 8.7% after 2 weeks. Further rubber swell tests using a S.A.E. standard SBR cup resulted in rubber swell of 0.62 mm. after 5 days at 70 C. and 0.93 mm. after 3 days at 120 C.

BLEND C Percent Product of Example 6 72 Solwent 36 26 LPE 504 2 DBA 0.1

BTZ 0.1

TPP 0 1 This was also found to be a useful fluid having a boiling point of 268 C. and a viscosity of 1698 est. at 40 C. Rubber swell tests (at 120 C.) on the synthetic rubber previously referred to resulted in a rubber swell of 4.8% after 3 days, 4.8% after 1 week and 4.0% after 2 weeks. In the case of S.A.E. SBR cups, rubber swell after 5 days at 70 C. was 0.39 mm. and after 3 days at 120 C. was 0.54 mm.

Solvent 36 is a glycol mono-ether mixture supplied by Union Carbide Corporation consisting of about 48% diethylene glycol mono-ethyl ether and 43% triethylene glycol mono-ethyl ether, together with small amounts of glycols and other glycol mono-ethyl and mono-methyl ethers. LPE 504 is a commercially available pentaerythritol tetraester supplied by Geigy (U.K.) LTD.

The effect of hygroscopicity on the boiling point of the product of Example 6, Blends B and C and Base Blend A was tested by exposing samples to 50% relative humidity at -F. for 16 hours. Results obtained were as follows:

TABLE II.-GLYCOL UREIHANE PROPERTIES Long term rubber swell test, percent volume increase at 70 C. in-

BzP. afiiii b'. Rubber test Glycol urethane C.) (cst.) specimen 3 days 1 week 2 weeks 4 weeks 8 weeks 12 week s Product ot- Example 1 all 2,872 {ifilfiiitttIII 13:; II: "3: :3 I llpppplll 25? 2-993 {$3 5255 2:2 1%; 13:? 13:2 15:? Example 5 281 3.860 {$552156 31% 5:2 3:3 5:3 '5'; Example 10 211 solid {stash- It; It; It? 23:? :32 Example 12 2B1 "teeters-. it 33. It? It; It 3 Emmple 15 Spllll igiiliiigii' "3:3 513 312 :3: Elplllplp 16 4,087 lg fififiaa jugii "ii? iii i11 E ample 17 294 8.116 {$115,12 4 Emllllllm $$2ltt=t3:-,.- -2.5 as -2.s""':: sis Emmi) 21 297 2,623 gfiifififlii" 13:2 15:: 1%? 1;; iii: 1( Elplmplp l2 poll {$352501 :1 13:3 323 di it? Test carried out at C.

Viscosity Long term rubber swel ilotesz, percent volume increase at in- B.P. at 40 0. Rubber test Blend C.) (cst.) specimen 3 days 1 week 2 weeks 4 weeks 8 weeks 12 weeks Base Blend A:

Plus 10% product of Ex. 14 Synthetic 1 9. 7 10.7 Plus 10% product of Ex. 15- d 9. 9 10.3 Plus 10% product of Ex. 18- 12. 2 11.3 Plus 10% product of Ex. 19 11.9 11. 6 Base Blend A 300 1,791 do 15.5

6. 6. 4 6. 0 5. 1 TE GDP 95% product 01 Ex. 11, 2g g 1 a7 5 e E 90% pr u t 0! E i 3 g 2 9 g .0 Ethyl diglycfl 100% 17. o 17. s 17. 2 16. 9 Product of Ex. 6A 46%, 'IEGDP 44%, Ethyl 288 1,716 2.3 2. 7 3.2 3.3 triglyc017%, Amine A 3%, plus the same com- 12. 5 13. 0 12. 3 12. 4

bination of additives as in Base Blend A.

1 Test carried out at 120 C.

I .A. repetition 0! Example 6 in which the reaction was carried out [or 3 hours at 100 C. and stripping was carried out at 200 C./2-1 mm. Hg.

We claim:

1. A hydraulic fluid consisting essentially of a blend of from 1% to 99% by weight, based on the total weight of the hydraulic fluids, of at least one glycol urethane having the general formula:

wherein R is selected from the group consisting of alkyl groups containing from 1 to 4 carbon atoms, allyl groups and groups having the formula R is an alkylene radical containing from 1 to 4 carbon atoms; R is selected from the group consisting of hydrogen atoms, alkyl radicals containing from 1 to 4 carbon atoms, the group andthe group f 1 1 R1-NHC;

R is an alkyl radical containing from 1 to 4 carbon atoms; R, is an alkylene group containing from 1 to carbon atoms; R; is selected from the group consisting of alkyl groups containing from 1 to 4 carbon atoms and the group and each n is the same or different and is an integer of from 1 to 6 and when any n is an integer greater than 1, each R may be the same or different, with at least one hydraulic fluid base stock selected from the group consisting of (poly) oxyalkylene glycol ether esters of dicarboxylic acids, esters of acetic, propionic or butyric acids with (11- or polyoxyalkylene glycols, polyoxyalkylene glycols, glycol ethers, orthoesters and borate esters.

2. A hydraulic fluid according to claim 1 wherein the glycol urethane or glycol urethanes consist of from 10% to 70% of the blend.

3. A hydraulic fluid according to claim 1 containing a hydraulic fluids base stock comprising at least one polyoxyalkylene glycol ether ester of a dicarboxylic acid.

4. A hydraulic fluid according to claim 1 containing a hydraulic base stock comprising at least one ester of a dior polyoxyalkylene glycol with an acid selected from the group consisting of acetic acid, propionic acid and butyric acid.

5. A hydraulic fluid according to claim 1 wherein each R is the same or difierent and is selected from the group consisting of ethylene groups and propylene groups; R is an alkylene group containing from 2 to 8 carbon atoms; and each n is an integar selected from the group consisting of 2 and 3.

6. A hydraulic fluid according to claim 1 containing from about 0.05 to 10% by weight of an organic corrosion inhibitor.

7. A hydraulic fluid according to claim 1 containing from about 0.05 to 10% by weight of an organic antioxidant.

8. A hydraulic fiuid according to claim 1 containing from about 0.05 to 10% by weight of an organic lubricity agent.

9. A method of transmitting power in a hydraulic system which method comprises introducing into the system a hydraulic fluid consisting essentially of at least one glycol urethane having the general formula:

wherein R is selected from the group consisting of alkyl groups containing from 1 to 4 carbon atoms, allyl groups and groups having the formula R is an alkylene radical containing from 1 to 4 carbon atoms; R is selected from the group consisting of hydrogen atoms, alkyl radicals containing from 1 to 4 carbon atoms, the group R is an alkyl radical containing from 1 to 4 carbon atoms; R is an alkylene group containing from 1 to 10 carbon atoms; R7 is selected from the group consisting of alkyl groups containing from 1 to 4 carbon atoms and the group LEON D. ROSDOL, Primary Examiner H. A. PITLICK, Assistant Examiner U.S. CL. X.R. 260482 B, 482 C 

